IT’S A VERY IMPORTANT VITAMIN: When treating infertility, vitamin D levels may be key. “The British researchers found that women with correct levels of vitamin D were 34 percent more likely to have a positive pregnancy test, 46 percent more likely to achieve a clinical pregnancy and a third more likely to have a live birth than women with low levels of vitamin D. . . . The researchers, from the University of Birmingham, noted that just 26 percent of women in the studies had sufficient levels of vitamin D.”